September's continuing resolution might keep the government funded through Nov. 18, but the first signs of yet another ugly shutdown showdown are already starting to appear.

With overall funding levels set, round four of the 2011 government shutdown fight isn't expected to center on conservatives' effort to cut more spending. Instead, in the House and Senate, Republicans are gearing up for a far more traditional battle over policy riders ranging from abortion to farm dust.

"Conservatives such as myself will be looking for every opportunity to advance good policy," Rep. Doug Lamborn(R-Colo.) said Thursday.

Rep. Mick Mulvaney (R-S.C.) agreed, saying, "I think if you're looking for a guide as to what riders we're looking for, it's the same things we tried to attach to H.R. 1 in the spring," referring to the House budget resolution that attracted hundreds of contentious amendments.

A senior Senate Democratic aide said some Republicans, particularly in the House, might be tempted to add policy riders to the upcoming spending bills, which could threaten Democratic support.

But the aide hopes that ultimately a compromise can be reached.

"The appropriations bills are not the place for them to act out on their anti-regulatory zeal," the aide said. "It's not the forum to make policy."

"We realize that the House has to go through a process where they calm down extreme elements in their caucus ... but policy riders almost never make it into the final product," the aide continued.

The first salvo in the rider war will likely come from the Senate, where conservatives are preparing a series of amendments to the minibus spending bills being considered.

The Senate last week began considering a package of three of the 12 annual spending bills — Agriculture, rural development, and Food and Drug Administration; Commerce, Justice and science; and Transportation and Housing and Urban Development — an effort to reduce the measures that will likely have to be rolled into a catchall package Congress will need to finish fiscal 2012 appropriations.

"We are working on an amendment list," a senior Democratic aide said.

Senate Majority Leader Harry Reid (D-Nev.) has said he hopes to have the chamber clear the legislation before the end of the week.

The Senate is scheduled to be on recess next week, but Reid — to keep to his time frame — indicated he would be willing to keep the Senate in session if the chamber can't approve the bill before Friday.

Sen. Mike Johanns (R-Neb.) will likely force a vote on an amendment that would forbid the use of funds for the regulation of farm dust.

"My legislation [would say], you can't regulate farm dust, that's absurd," Johanns said. "It's just indicative of what this administration is about. They are so incredibly out of touch. You can't farm without creating dust."

Democrats say the issue is a red herring — the Environmental Protection Agency and Department of Agriculture say no regulation is forthcoming. But Johanns said he has been in contact with the EPA and feels it has not been clear.

"Lisa Jackson of the EPA has declared repeatedly that there is no [farm] dust [rule afoot]," Johnson said.

Other possible amendments to the package include proposals from Sen. Rand Paul (R-Ky.) to cut spending in the individual bills.

"We will bring it down so that we will actually be changing the money that is spent," Paul said.

Sen. Mark Begich (D-Alaska) might offer an amendment to the Agriculture spending bill that would prevent the Food and Drug Administration from spending any funds on approving genetically engineered salmon.

The agency is considering an application by AquaBounty Technologies Inc. to grow genetically engineered salmon in Panama for importation into the United States, with plans to eventually grow the fish in the U.S., according to his office.

The fish would grow faster than natural fish, and some lawmakers, including Begich, have concerns about the effect of escaped fish on wild salmon stocks, the suitability of such fish for human consumption and the FDA's approval process for the fish.

But the main front of the war will almost certainly be in the House, where Speaker John Boehner (R-Ohio) and Majority Leader Eric Cantor (R-Va.) will likely need the help of Democrats to pass either an omnibus or a series of minibus bills.

With leadership remaining adamant that the funding levels agreed to in the August debt deal be used, House conservatives are gearing up to take a stand on policy riders instead.

Rep. Jeff Flake (R-Ariz.), a thorn in the side of leadership, is circulating a letter calling on Boehner to use the sort of open process to pass the fiscal 2012 spending package as he used on H.R. 1.

"Given the likely truncated process forthcoming ... shutting down an open floor process would clearly send taxpayers the wrong message," Flake writes in the letter.

An Oct. 4 legislative bulletin from the conservative Republican Study Committee listed several riders that are priorities for the right. The list includes a ban on federal funding for abortion providers, measures aimed at halting new environmental and Net neutrality regulations, and efforts to strip funding for National Public Radio, the Palestinian Authority and the Legal Services Corp.

"I expect a defunding of the Palestinian Authority to come up as a larger issue," a senior GOP aide confirmed, in addition to the EPA and abortion riders.

Securing many of these riders would go a long way toward easing the bruised feelings many conservatives have over the stopgap bill — and the higher spending levels that were agreed to under the debt deal when compared to the House GOP's budget.

"It's sort of hard to live with the spending levels if we don't have any riders at all," Mulvaney said.

The problem for Boehner is that a rider-laden spending bill won't pass the Senate. Stripping out some riders will likely cost him Republican votes, meaning he could be forced to rely on Democrats. But to get them, he'll need to strip even more amendments, losing more Republicans. The struggle will bring with it the now-familiar bracing for a government shutdown.

"I think passing the omnibus or minibuses is going to be a challenge. Getting the votes for it is going to be a challenge," Rep. John Campbell (R-Calif.) said.

Campbell said breaking up the appropriations bills into minibuses could provide flexibility.

"Sometimes you can break a bill into three and get a different coalition. For example, look at the trade agreements that just passed. There's a whole different coalition that voted for the agreements than voted for the TAA," Campbell said, referring to last week's passage of trade deals with Colombia, South Korea and Panama, as well as Trade Adjustment Assistance.

But as long as there are riders, Democrats are unlikely to join any of those coalitions.

"Absolutely not," Rep. Debbie Wasserman Schultz (D-Fla.) said Thursday, charging the demand for riders is "one more countless example of how they don't understand the No. 1 issue is jobs and the economy. People don't want legislation that controls their personal life."